1. Field of the Invention
The present invention relates to a heat dissipation fan, and more particularly to a heat dissipation fan that has a lubricating bearing with an oil guide to prolong the life of the heat dissipation fan.
2. Description of Related Art
With reference to FIG. 5, a conventional heat dissipation fan in accordance with the prior art comprises a casing (30) and a fan (32) rotatably mounted in the casing (30). A stator (34) with an electromagnet formed in the stator (34) is securely fixed in the casing (30). A permanent magnet (322) is mounted in the fan (32) to be a rotor, such that the fan (32) can rotate due to the interaction between the magnetic forces in stator (34) and the permanent magnet (322). A sleeve (38) is securely mounted on a base (302) formed in the casing (30) and pressed into the stator (34). A lubricating bearing (36) with lubrication oil contained therein is pressed into the sleeve (38). A shaft (324) extends from the fan (32) and through the bearing (36). A locking disk (50) is mounted on the free end of the shaft (324) to securely hold the bearing (36) on the shaft (324) so the fan (32) can rotate relative to the casing (30) with very little friction. Because the lubrication oil will flow out of the bearing (36) when the fan (32) is in operation, a seal (42) and a gasket (40) must be mounted on the shaft (324) at each end of said lubricating bearing (36) to keep the lubrication oil from leaking out of the sleeve (38) and drying out the bearing (36).
However, during the assemble of the conventional heat dissipation fan, the sleeve (38) must first be pressed into the casing (30) base (302). Then the casing (30) must be turned over to install the circuit board (35) and stator (34) in the casing (30) and the lubricating bearing (36) into the sleeve (38) with a specific hand tool. After mounting the seal (42) and the gasket (40) on the shaft (324), the shaft (324) extends through the central hole of the bearing (36). The casing (30) must be turned over again to install the second seal (46), gasket (44) and the locking disk (50) on the free end of the shaft (324) with a specific hand tool. Finally, a cover (39) is mounted on the base (302) of the casing (30) to close the base (302). Consequently, the assembly of the conventional heat dissipation fan is very difficult and tedious. In addition, because the heat dissipation fan usually works with a small object like the CPU of a computer, the volume of the heat dissipation fan must be small, and the components of the heat dissipation fan are very tiny. This will further increase the difficulty and tedium of assembling the conventional heat dissipation fan. Furthermore, the conventional heat dissipation fan does not have any oil guilds, so the lubrication oil easily flows out of the sleeve (38). Consequently, the bearing will easily dry out, and the useful life of the heat dissipation fan will be decreased.
To overcome the shortcomings, the present invention tends to provide an improved heat dissipation fan to mitigate or obviate the aforementioned problems.